Quick coupler circuit for construction equipment

ABSTRACT

A switch ( 15 ) is configured so as to be operated with two positions of a locked position when an attachment is held and an unlocked position when an attachment is released. Furthermore, a control device ( 16 ) receives an operation signal that is output when the switch ( 15 ) is operated to the locked position or the unlocked position and switches and controls an electromagnetic switching valve ( 13 ) so that the pressure of a hydraulic pump begins to rise and so that, at a stage when a predetermined time has passed, the pressure raising in the hydraulic pump is stopped.

TECHNICAL FIELD

The present invention relates to a quick coupler circuit forconstruction equipments for easily attaching or detaching an attachmentsuch as a bucket or a breaker. Priority is claimed on Japanese PatentApplication No. 2010-140514, filed Jun. 21, 2010, the content of whichis incorporated herein by reference.

BACKGROUND ART

In the related art, as illustrated in FIG. 3, a hydraulic shovel(construction equipment) 1 includes a lower travelling body 2, an upperpivoting body 3 pivotably provided on the lower travelling body 2, and aworking machine 4 installed on the upper pivoting body 3 which is freeto be raised or lowered in a vertical direction. Furthermore, theworking machine 4 includes a boom 5, a rear end of which is supported bythe upper pivoting body 3 in a freely turnable manner, an arm 6, a rearend of which is supported by a leading end of the boom 5 in a freelyturnable manner, and a bucket (attachment) 7 installed on the leadingend side of the arm 6 in a freely turnable manner. The working machine 4is formed in a multiple joint form. Moreover, hydraulic oil is suppliedand discharged depending on the lever operation of an operator, a boomcylinder 8, an arm cylinder 9 and a bucket cylinder 10 (workingactuator) are each extended and retracted, and the boom 5, the arm 6 andthe bucket 7 are each turned.

Meanwhile, the construction equipment 1 has been known which isconfigured so that various attachments 7 such as a bucket, a breaker anda crusher can be attached to and detached from the leading end of thearm 6. Since the attachments 7 can be exchanged in this constructionequipment 1, a piece of the construction equipment 1 can be used formultiple purposes and multiple functions. hi addition, constructionequipment 1 has been known which includes a quick coupler circuit andeasily and rapidly performs attachment and detachment of attachment 7 byoperation of a switch by the operator.

Generally, the quick coupler circuit (quick coupler B) is providedbetween the leading end of the arm 6 and the attachment 7. Moreover, thequick coupler circuit includes a quick coupler cylinder that is extendedand retracted by supplying and discharging of the hydraulic, oil tohold/detach the attachment 7, a hydraulic pump, an electromagneticswitching valve that switches a supplying direction of the hydraulic oilsupplied from the hydraulic pump to a working actuator (the boomcylinder 8, the arm cylinder 9 and the bucket cylinder 10) side or aquick coupler cylinder side, a coupler switching valve for extending orretracting the quick coupler cylinder by switching the supplyingdirection of the hydraulic oil to the quick coupler cylinder, and acontrol device that switches and controls the electromagnetic switchingvalve and the coupler switching, valve based on a pilot signal(operation signal) that is output by operation of the switch (forexample, see Patent Document 1).

CITATION LIST Patent Document

[Patent Document 1] Japanese Unexamined Patent Application, FirstPublication No. 2007-327291

SUMMARY OF INVENTION Problem to be Solved by the Invention

Herein, in order that the extension and retraction operation (attachmentand detachment of the attachment 7) of the quick coupler cylinder isreliably performed, there is a need for a pump pressure-raisingoperation of an operator. For this reason, in the above-mentioned quickcoupler circuit of the related art, the electromagnetic switching valvehas been used. Moreover, the pilot signal for forcibly raising thepressure of the pump is controlled, and the pressure of the hydraulicpump is forcibly raised. Furthermore, in the above-mentioned quickcoupler circuit of the related art, the electromagnetic switching valveand the coupler switching valve are switched and driven depending on theswitch operation, and a three-position switch and a relay circuit arerequired so as to control two valves.

That is, in the quick coupler circuit of the related art, a switchoperated by three positions and a relay circuit are combined with eachother to perform the control of raising the pressure of the hydraulicpump. The three positions include a working position when extending andretracting the working actuator to perform working, a locked positionwhen extending (or retracting) the quick coupler cylinder to hold(install) the attachment 7, and an unlocked position when retracting (orextending) the quick coupler cylinder to detach the attachment 7.Moreover, when exchanging the attachment 7, the locked position and theunlocked position are used, and the pressure of the hydraulic pump isalways raised between the locked position and the unlocked position.

For this reason, only the performed control is whether or not thepressure of the hydraulic pump always rises or the pressure of thehydraulic pump does not always rise so that the quick coupler cylinderis extended or retracted, depending on the position of the switch. Thatis, it is impossible to control the time and the timing of the pressureraising. As a result, the movements of working actuators 8, 9 and 10(working machine 4) are unstable while the pressure of the pump rises.Furthermore, unnecessary pump pressure raising time is generated, andthus fuel efficiency is degraded.

In view of the above, an object of the present invention is to provide aquick coupler circuit for construction equipment that is able to controlthe time and the timing of the pressure raising, stabilizes theoperation of the working machine while the pressure of the hydraulicpump rises, and is able to improve the fuel efficiency.

Solution to Problem

In order to achieve the above-mentioned object, the present inventionadopts the following means.

The quick coupler circuit for construction equipment of the presentinvention is a quick coupler circuit for construction equipment forattaching or detaching the attachment to or from the working machine.Moreover, the quick coupler circuit of the present invention includes aquick coupler cylinder that is subjected to extension and retractiondriving and holds/detaches the attachment to or from the workingmachine; a hydraulic pump; an electromagnetic switching valve thatswitches forced pressure raising of the hydraulic pump; a couplerswitching valve for performing extension and retraction driving of thequick coupler cylinder by switching a supplying direction of hydraulicoil to the quick coupler cylinder; and a control device that switchesand controls the electromagnetic switching valve and the couplerswitching valve, respectively. Furthermore, in the quick coupler circuitof the present invention, the switch for switching and operating theelectromagnetic switching valve and the coupler switching valve isoperated with two positions of a locked position where extending andretracting the quick coupler cylinder to hold the attachment, and anunlocked position where extending and retracting the quick couplercylinder to detach the attachment. Furthermore, in the quick couplercircuit of the present invention, the control device switches andcontrols the coupler switching valve by receiving the operation signalthat is output by operating the switch to the locked position or theunlocked position in addition, in the quick coupler circuit of thepresent invention, the control device switches and controls theelectromagnetic switching valve so that the pressure raising of thehydraulic pump begins by operation of the switch and the pressureraising of the hydraulic pump is stopped at a stage when a predeterminedtime elapses.

Advantageous Effects of Invention

In the quick coupler circuit for construction equipment of the presentinvention, the quick coupler circuit transmits the operation signal ofthe switch to the electromagnetic switching valve via the controldevice. For that reason, it is possible to control the time when theelectromagnetic switching valve is switched so as to raise the pressureof the hydraulic pump. That is, the control device switches and controlsthe electromagnetic switching valve so that the pressure of thehydraulic pump rises, based on the operation signal that is output byoperating the switch to the locked position or the unlocked position.After that, at a stage when a predetermined time elapses, the controldevice is able to control the pump pressure raising time and timing byswitching and controlling the electromagnetic switching valve so thatthe pressure raising of the hydraulic pump is completed.

Thereby, it is possible to perform the control so that the pressure ofthe hydraulic pump rises only while the quick coupler cylinder is moved,by operating the switch operated with two positions of the lockedposition and the unlocked position. Thus, since the pressure raisingtime can be minimalized compared to the quick coupler circuit of therelated art, it is possible to suppress the unstable movement of eachactuator (working machine) during pressure raising of the pump to theminimum. Furthermore, since an unnecessary pressure raising time of thepump is reduced, the fuel efficiency is improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram that illustrates a quick coupler circuit for aconstruction equipment according to an embodiment of the presentinvention.

FIG. 2 is a diagram that illustrates a quick coupler circuit for aconstruction equipment according to modified example of an embodiment ofthe present invention.

FIG. 3 is a diagram that illustrates a hydraulic shovel (constructionequipment).

DESCRIPTION OF EMBODIMENTS

Hereinafter, a quick coupler circuit for construction equipmentaccording to an embodiment of the present invention will be describedreferring to FIGS. 1 and 3,

Construction equipment 1 of the present embodiment is a hydraulic shovel(see FIG. 3), and includes a quick coupler circuit A for easilyattaching or detaching various attachments 7 such as a bucket and abreaker to or from a leading end of an arm 6 (working machine).

Moreover, as illustrated in FIG. 1, the quick coupler circuit A of thepresent embodiment includes a quick coupler cylinder 11, a hydraulicpump (for example, variable capacity pump) 12, an electromagneticswitching valve (solenoid valve) 13, a coupler switching valve 14, aswitch 15, and a control device 16.

The quick coupler cylinder 11 is a member for holding(installing)/detaching the attachments 7 to or from the leading end ofthe arm 6 by being extended and retracted by supplying and dischargingof the hydraulic oil. The quick coupler cylinder 11 is built in anattaching and detaching apparatus attached to the leading end of the arm6, and is provided between the leading end of the arm 6 and theattachment 7. Furthermore, in the quick coupler circuit A of the presentembodiment, hydraulic pipes are each connected to a piston chamber 11 aand a rod chamber 11 b of the quick coupler cylinder 11 so that when thequick coupler cylinder 11 is extended, the attachment 7 is fixed, andwhen the quick coupler cylinder 1 is retracted, the attachment 7 isremoved.

The electromagnetic switching valve 13 is able to change a supplyingdirection of the hydraulic oil supplied by the hydraulic pump 12 of ahydraulic source to a working actuator (a boom cylinder 8, an armcylinder 9 and a bucket cylinder 10) side of the working machine 4 orthe quick coupler cylinder 11 side. The electromagnetic switching valve13 is connected to the hydraulic pump 12, each of the working actuators8, 9 and 10, and a coupler switching valve 14 via the hydraulic pipes,

The coupler switching valve 14 is a member for extending or retractingthe quick coupler cylinder 11. The coupler switching valve 14 isconnected to the quick coupler cylinder 11 by the hydraulic pipes, andis able to change the supplying direction of the hydraulic oil suppliedfrom the hydraulic pump 12 to the quick coupler cylinder 11.

The switch 15 is used when an operator changes the electromagneticswitching valve 13 and the coupler switching valve 14 at the time ofexchanging (attaching or detaching) the attachment 7. The switch 15 isconnected to the control device 16 using a wire harness. Furthermore,the switch 15 of the present embodiment is operated with two positionsof the locked position where extending the quick coupler cylinder 11 tohold the attachment 7 and the unlocked position where retracting thequick coupler cylinder 11 to detach the attachment 7.

The control device 16 is a member for switching and controlling theelectromagnetic switching valve 13 and the coupler switching valve 14,respectively. The control device 16 is connected to the electromagneticswitching valve 13 and the coupler switching valve 14 using the wireharness. The control device 16 of the present embodiment switches andcontrols the coupler switching valve 14 by receiving the operationsignal that is output by the operation of the switch 15 to the lockedposition or the unlocked position. Furthermore, the control device 16 ofthe present embodiment switches and controls the electromagneticswitching valve so that pressure raising of the hydraulic pump 12 beginsby the operation of the switch 15, and pressure raising of the hydraulicpump 12 is stopped at a stage when a predetermined time elapses.

When exchanging (attaching or detaching) the attachment 7 with the quickcoupler circuit A of the present embodiment, firstly, an operatoroperates the lever, and drives the working actuators 8, 9 and 10.Moreover, an operator places the attachment 7 attached to on the leadingend of the arm 6 at a predetermined position.

Next, when an operator turns the switch 15 to the unlocked position, theoperation signal is input to the control device 16, Moreover, theswitching signals are each output to the electromagnetic switching valve13 and the coupler switching valve 14 from the control device 16 basedon the operation signal. Moreover, the electromagnetic switching valve13 is switched by the switching signal that is output from the controldevice 16, and the pressure of the hydraulic pump 12 rises. Furthermore,the coupler switching valve 14 is switched by the switching signal thatis output from the control device 16, and hydraulic oil is supplied anddischarged so that the quick coupler cylinder 11 is retracted. Theholding state of the attachment 7 installed on the leading end of thearm 6 is released by retraction of the quick coupler cylinder 11, andthe attachment 7 is detached from the leading end of the arm 6.

Furthermore, in the present embodiment, after the electromagneticswitching valve 13 is switched and controlled by the control device 16(after an operator operates the switch to the unlocked position), forexample, at a stage when a predetermined time of about 10 secondselapses, the electromagnetic switching valve 13 is switched andcontrolled, and the pressure raising of the hydraulic pump 12 isstopped. That is, when an operator operates the switch to the unlockedposition, the quick coupler cylinder 11 is retracted, and the attachment7 is detached from the leading end of the arm 6, the electromagneticswitching valve 13 is automatically switched and controlled by thecontrol device 16, and the oil pressure returns to a normal pressure atthe time of work.

Thereby, as in the quick coupler circuit of the related art, when anoperator turns the switch 15 to the unlocked position, the pressure doesnot rise so as to always contract the quick coupler cylinder 11. Forthat reason, the pressure raising time of the hydraulic pump 12 becomesminimum. For this reason, the unstable movement is also suppressed tothe minimum when driving the respective working actuators 8, 9 and 10.Furthermore, the unnecessary pump pressure raising time is also reduced.

Next, when attaching a new attachment 7 to the leading end of the arm 6,firstly, the working machine 4 is driven so that the new attachment 7 isplaced at a predetermined position of the leading end side of the arm 6by the lever operation of the operator. At this time, since therespective working actuators 8, 9 and 10 are not unstably moved, it ispossible to very suitably place the leading end side of the arm 6 at apredetermined position.

Moreover, an operator operates the switch to the locked position in astate where the leading end side of the arm 6 is placed at apredetermined position. Then, the operation signal is input to thecontrol device 16, and the switching signals are output to theelectromagnetic switching valve 13 and the coupler switching valve 14from the control device 16 based on the operation signal, respectively.The pressure of the hydraulic pump 12 rises by the switching signalsthat are output from the control device 16. Furthermore, the couplerswitching valve 14 is switched by the switching signals that are outputfrom the control device 16, and the hydraulic oil is supplied anddischarged so that the quick coupler cylinder 11 is extended. Moreover,a connection pin and a wedge of the new attachment 7 is caught by theextension of the quick coupler cylinder 11, and the new attachment 7 isconnected to the leading end of the arm 6 and is held (installed).

Furthermore, even when the attachment 7 is installed, after theelectromagnetic switching valve 13 is switched and controlled (after anoperator operates the switch to the locked position) by the controldevice 16, for example, at a stage when a predetermined time of about 10seconds elapse, the electromagnetic switching valve 13 is switched andcontrolled, and pressure raising of the hydraulic pump 12 is stopped.That is, when an operator operates the switch to the locked position,the quick coupler cylinder 11 is extended, and the attachment 7 isinstalled to the leading end of the arm 6, the electromagnetic switchingvalve 13 is automatically switched and controlled by the control device16, and the oil pressure returns to the normal pressure at the time ofwork.

For that reason, when the switch 15 is turned to the locked position,the pressure of the hydraulic pump 12 does not rise so as to alwaysextend the quick coupler cylinder 11. For that reason, pressure raisingof the hydraulic pump 12 is performed in a minimum pressure raisingtime. Thus, even at the time of installing the attachment 7, theunstable movement of the respective working actuators 8, g and 10 issuppressed to the minimum when driving the respective working actuators8, 9 and 10, Furthermore, the unnecessary pressure raising time is alsoreduced.

Furthermore, when installing the attachment 7, after the electromagneticswitching valve 13 is switched and controlled and the oil pressurereturns to the normal pressure at the time of work, the workingactuators 8, 9 and 10 may be driven by the control device 16, for apredetermined time, for example, 5 seconds. In this case, it is possibleto check whether or not the installed attachment 7 is reliably(suitably) connected and installed.

Thus, in the quick coupler circuit A for construction equipment of thepresent embodiment, each quick coupler circuit A transmits the operationsignal output from the switch 15 to the electromagnetic switching valve13 via the control device 16. For that reason, it is possible to controlthe time when the electromagnetic switching valve 13 is switched so asto raise the pressure of the hydraulic pump 12. That is, after thecontrol device 16 switches and controls the electromagnetic switchingvalve 13 so as to raise the pressure of the hydraulic pump 12, based onthe operation signal that is output by operating the switch 15 to thelocked position or the unlocked position, by switching and controllingthe electromagnetic switching valve 13 so as to finish pressure raisingof the hydraulic pump 12 at a stage when a predetermined time elapses,the pump pressure raising time and timing can be controlled.

For that reason, it is possible to perform the control so that thepressure of the hydraulic pump 12 rises only while the quick couplercylinder 11 is moved, by operating the switch 15 that is operated withtwo positions of the locked position and the unlocked position. Thus,compared to the quick coupler circuit of the related art, pressureraising of the hydraulic pump 12 is performed in a minimum pressureraising time in the quick coupler circuit A of the present invention.For that reason, it is possible to suppress the unstable movement of therespective working actuators 8, 9 and 10 (working machine 4) to minimumduring pressure raising of the pump. Furthermore, since the unnecessarypump pressure raising time is reduced, the fuel efficiency is improved.

Although an embodiment of the quick coupler circuit for constructionequipment related to the present invention has been described, thepresent invention is not limited to the above-mentioned embodiment butmay be suitably changed within a scope that does not depart from thegist thereof. For example, in the present embodiment, although the casewhere the construction equipment 1 is the hydraulic shovel has beendescribed the construction equipment related to the present inventionmay be other construction equipments such as a shovel loader.

Furthermore, in the quick coupler circuit A of the present embodiment,the hydraulic pipes are each connected to the piston chamber 11 a andthe rod chamber 11 b of the quick coupler cylinder 11 so that when thequick coupler cylinder 11 is extended, the attachment 7 is fixed, andwhen the quick coupler cylinder 11 is retracted, the attachment 7 isdetached. On the contrary to the present embodiment, as illustrated inFIG. 2, the hydraulic pipes may be each connected to the piston chamber11 a and the rod chamber 11 b of the quick coupler cylinder 11 so thatwhen the quick coupler cylinder 11 is extended, the attachment 7 isdetached, and when the quick coupler cylinder 11 is retracted, theattachment 7 is fixed.

Moreover, in the ease of having the above-mentioned configuration, onthe contrary to the present embodiment, when an operator operates theswitch to the unlocked position, the switching signals are each outputto the electromagnetic switching valve 13 and the coupler switchingvalve 14 from the control device 16. Moreover, the electromagneticswitching valve 13 is switched and the pressure of the hydraulic pump 12rises. Furthermore, the coupler switching valve 14 is switched by theswitching signal that is output from the control device 16, and thehydraulic oil is supplied and discharged so that the quick couplercylinder 11 is extended. In this manner, the holding state of theattachment 7 installed to the leading end of the arm 6 is released bythe extension of the quick coupler cylinder 11, and the attachment 7 isdetached from the leading end of the arm 6.

Furthermore, after the electromagnetic switching valve 13 is switchedand controlled (after an operator operates the switch to the unlockedposition) by the control device 16, for example, at a stage when apredetermined time of about 10 seconds elapses, the electromagneticswitching valve 13 is switched and controlled, and pressure raising ofthe hydraulic pump 12 is stopped.

That is, when an operator operates the switch to the unlocked position,the quick coupler cylinder 11 is extended, and the attachment 7 isdetached from the leading end of the arm 6, the electromagneticswitching valve 13 is automatically switched and controlled by thecontrol device 16, and the oil pressure returns to the normal pressureat the time of work.

For that reason, pressure raising of the hydraulic pump 12 is performedin a minimum pressure raising time. As a result, when driving therespective working actuators 8, 9 and 10, the unstable movement of therespective working actuators 8, 9 and 10 is suppressed to the minimum.Furthermore, the unnecessary pump pressure raising time is reduced.

Furthermore, even when a new attachment 7 is installed to the leadingend of the arm 6, on the contrary to the present embodiment, an operatoroperates the switch to the locked position in a state where the leadingend side of the arm 6 is placed at a predetermined position. Then, theswitching signals are each output to the electromagnetic switching valve13 and the coupler switching valve 14 from the control device 16, andthus the pressure of the hydraulic pump 12 rises. Furthermore, thecoupler switching valve 14 is switched by the switching signal that isoutput from the control device 16, and the hydraulic oil is supplied anddischarged so that the quick coupler cylinder 11 is retracted. In thismanner, the connection pin or the wedge of the new attachment 7 iscaught by the retraction of the quick coupler cylinder 11, and the newattachment 7 is connected to the leading end of the arm 6 and is held(installed).

Furthermore, even when installing the above-mentioned attachment 7,after the electromagnetic switching valve 13 is switched and controlledby the control device 16, for example, at a state when a predeterminedtime of about 10 seconds elapses, the electromagnetic switching valve 13is switched and controlled, and pressure raising of the hydraulic pump12 is stopped. That is, when an operator operates the switch to thelocked position, the quick coupler cylinder 11 is retracted, and theattachment 7 is installed to the leading end of the arm 6, theelectromagnetic switching valve 13 is automatically switched andcontrolled by the control device 16, and the oil pressure returns to thenormal pressure at the time of work.

For that reason, when the switch 15 is turned to the locked position,the pressure of the hydraulic pump 12 does not rise so as to alwayscontract the quick coupler cylinder 11. As a result, the hydraulic pump12 is performed in a minimum pressure raising time, Thus, even at thetime of installing the attachment 7, when driving the respective workingactuators 8, 9 and 10, the unstable movement of the respective workingactuators 8, 9 and 10 is suppressed to the minimum. Furthermore, theunnecessary pump pressure raising time is reduced.

INDUSTRIAL APPLICABILITY

According to the present invention, there is provided a quick couplercircuit that is able to control the time when the electromagneticswitching valve is switched so as to raise the pressure of the hydraulicpump.

Furthermore, according to the present invention, in the quick couplercircuit for construction equipment, the pressure raising time of thehydraulic pump can be reduced to the minimum level. For that reason, itis possible to suppress the unstable movement of each actuator to theminimum during pressure raising of the pump. Furthermore, since theunnecessary pump pressure raising time is reduced, the fuel efficiencyis improved.

REFERENCE SIGNS LIST

1 hydraulic shovel (construction equipment)

2 lower travelling body

3 upper pivoting body

4 working machine

5 boom

6 arm

7 bucket (attachment)

8 boom cylinder (working actuator)

9 arm cylinder (working actuator)

10 bucket cylinder (working actuator)

11 quick coupler cylinder

11 a piston chamber

11 b rod chamber

12 hydraulic pump

13 electromagnetic switching valve

14 coupler switching valve

15 switch

16 control device

A quick coupler circuit for construction equipment

B quick coupler

1. A quick coupler circuit for construction equipments for attaching ordetaching an attachment to or from a working machine, the quick couplercircuit comprising: a quick coupler cylinder that is subject toextension and retraction driving and holds/detaches the attachment to orfrom the working machine; a hydraulic pump; an electromagnetic switchingvalve that switches forced pressure raising of the hydraulic pump; acoupler switching valve for performing extension and retraction drivingof the quick coupler cylinder by switching a supplying direction ofhydraulic oil to the quick coupler cylinder; and a control device thatswitches and controls the electromagnetic switching valve and thecoupler switching valve, respectively, wherein a switch for switchingand operating the electromagnetic switching valve and the couplerswitching valve is configured so as to be operated with two positions ofa locked position where extending and retracting the quick couplercylinder to hold the attachment, and an unlocked position whereextending and retracting the quick coupler cylinder to detach theattachment, and the control device switches and controls the couplerswitching valve by receiving an operation signal that is output byoperating the switch to the locked position or the unlocked position,and switches and controls the electromagnetic switching valve so thatthe pressure raising of the hydraulic pump begins by operation of theswitch and the pressure raising of the hydraulic pump is stopped at astage when a predetermined time elapses.